Motor oil, engine oil, or engine lubricant, generally referred to as oil, is any of various substances comprising base oils enhanced with additives, e.g., anti-wear additive and detergents, dispersants and, for multi-grade oils viscosity index improvers. Lubricating oils can also contain corrosion inhibitors, e.g., rust and oxidation inhibitors. Oil can be used for lubrication of internal combustion engines. The oil reduces friction and wear on moving parts and to clean the engine from sludge (one of the functions of dispersants) and varnish (detergents). The oil can also neutralize acids that originate from fuel and from oxidation of the lubricant (detergents), improves sealing of piston rings, and cool the engine by carrying heat away from moving parts.